What is the difference between Use Case, Test Scenario and Test Case?

Use Case: Use case define system requirements from user's view

Test Scenario: Test Scenario Identify paths/conditions to be tested

Test Case: Test Case Execute and validate system behavior

Example :

• Use Case (User Registration): Describes how a user interacts with the system to register, including steps like providing username, password, and email.
• Test Scenario (Test Login with Valid Credentials): Outlines a situation to be tested, such as logging in with correct username and password, and verifying successful login.
• Test Case (Verify Error Message for Invalid Password): Provides detailed steps for testing a specific functionality, such as entering an incorrect password and confirming the system displays the expected error message.